NtpNetworkException when awaiting RequestTimeAsync()

[adolgov]

I'm trying to run a basic ntp time fetch in Xamarin.Android.

var client = new NtpClient();
var dt = await client.RequestTimeAsync();

While it's a simple example, I'm getting a NtpNetworkException with message This method is not implemented by this class.

The inner exception stack trace mentions:
at System.Net.EndPoint.Serialize () [0x00000] in /Users/builder/data/lanes/4009/72366f70/source/mo…

Any suggestions as to what I can try?
Version is latest from NuGet 1.0.9

[adolgov]

Same behavior (same exception type/message in ErrorOccurred event) when using the non-async calls

var client = new NtpClient(KnownNtpServers.NorthAmericaOrg);

client.TimeReceived += Client_TimeReceived;
client.ErrorOccurred += Client_ErrorOccurred;
client.BeginRequestTime();

[Yortw]

Sorry for the delayed reply, I have been away and was not in a position to do development or check GitHub.

I'm also sorry this isn't working for you. It appears to just be broken. I swear I tested it on Android before publishing, but it doesn't work now and it doesn't look like it ever did so I don't know what happened.

The basic problem is that Xamarin Android purports to support all the same socket API's as the desktop framework/iOS etc. but at least one of them throws a NotImplementedException and doesn't really work. Specifically calling System.Net.Sockets.Socket.Connect and passing a DnsEndPoint instance throws an exception from the EndPoint base class used by DnsEndPoint. I haven't found any way around this. I'm not sure what the point of DnsEndPoint is in Xamarin Android if you can't pass it to a socket.

However, I have found the same code works with an IpEndPoint, so it may be possible to do a manual DNS resolution of the server name to IP, then pass the IP to the socket. However I haven't had time yet to confirm this, and because it's (probably) (marginally) less efficient I'd prefer to only do it on Android, so it will need either a new implementation or some conditional compilation logic in the shared code file.

I'll let you know if/when I've managed to find a solution.

Thanks for reporting the problem.

[adolgov]

Thank you for your response.

Let me know if I can help test a potential solution.

[Yortw]

Hi,

I've published a beta package (https://www.nuget.org/packages/Yort.Ntp.Portable/1.0.10-beta) to Nuget . Make sure you turn on the 'pre-release' option in VS to see the new version.

I've tested it on a Samsung Galaxy S5 on Android 6.0.1 and it seems to work.

Please try that package and let me know if it works for you.

Thanks.

[adolgov]

The new version works. Thanks for the quick fix!

[Yortw]

No problem. Thanks for reporting it.